Haven't much time to check price and this topic but i fixed price for daggers, price are firm.
Level 0 - 500 FGs
Level 5 76ee - 400 FGs
Level 5 80ee - 500 FGs
Level 15 - 1,500 FGs
Level 20 - 600 FGs
Level 30 - 400 FGs
Level 35 - 900 FGs
Level 40 - 1,500 FGs
Level 50 120ee - 3,000 FGs
Level 50 176ee - 11,500 FGs